Virgin Australia is strategically important because they’re one of two significant airlines in Australia. Qantas is closely tied through a joint venture with American Airlines. So most airlines outside of the oneworld alliance (and Emirates) go looking for domestic feed for their long haul Australia routes with their competitor, Virgin Australia.
Virgin Down Under has been linked with Delta Air Lines through a joint business venture, leaving United Airlines in the cold. Its Australia flights have largely had to survive on local market passengers, rather than connecting people from all over Australia. That’s changing.